Weather, extreme heat, and everyday spending in cities: Evidence from longitudinal and nationwide credit card transactions in South Korea

As weather extremes become more frequent and persistent, cities need to understand how weather conditions are associated with everyday spending. Yet, existing research rarely provides a comprehensive picture of these relationships across spending amount, transaction frequency, sectoral composition, and cross-city variation. By linking nationwide credit card transactions from South Korea covering 2019 to 2020 with city-level meteorological data, this study examines associations of apparent temperature, precipitation, and extreme-heat persistence with everyday spending. Using 20– 25 ° C as the reference range, the results show that days with apparent temperatures of 33 ° C or higher were associated with an estimated 3.44% increase in overall transactions and an estimated 2.30% decrease in overall expenditure. Sectoral patterns were uneven, with higher transactions and expenditure in several retail, restaurant, and recreation categories but lower transactions and expenditure in Home and Internet Shopping. Beyond heat on a given day, a 10-mm increase in precipitation was associated with 1.05% fewer transactions and 0.94% lower expenditure. Meanwhile, each additional extreme-heat day during the preceding three days was associated with declines of 0.34% in transaction frequency and 1.60% in expenditure. A cross-city comparison further suggests that climatic context, coastal location, age structure, and population density were associated with heterogeneity in spending responses to weather. As global warming increases heat exposure, sectors and cities may face different economic gains and losses. Heat-adaptation strategies should therefore account for daily service demand, vulnerable populations, and local weather sensitivity.